A stepwise and orthogonal approach of two independent click reactions directly on the solid phase gives easy access to doubly modified DNA. Firstly, 5′-ethynyl-2′-deoxyuridine reacts directly with an azide-modified porphyrin; secondly, 5′-azido-2′-deoxyuridine is generated in situ from 5′-iodo-2′-deoxyuridine, which enables a click reaction with an alkyne-functionalized pyrene. The doubly modified DNA was characterized as a light-harvesting system.
Schmidt et al. (Thu,) studied this question.